Add phpunit/phpunit as dev dependancy
Use  preg_replace_callback() instead of the /e modifier
Merge pull request #5 from sanpii/php5.5

Php5.5
TokensCollection is tested
minor changes : details errors, html report contains info about test
more details in error messages
remove unused files
specifications to determine creation of mutants. Random by default
tool can be used with phar archive
documentation updated
minor refractoring in mutaters
minor refractoring in specification
minor refractoring in mutaters
fixes incoherence introduced by #2b60fe61e6322a966b6e2d5ca78dbc81b71977f5
phar is updated
fixes bug introduced by #2b60fe61e6322a966b6e2d5ca78dbc81b71977f5
fixes #3 - minimum stability in composer
fixes typo in the readme file
Merge remote-tracking branch 'upstream/master'